Moving of minor child out of state

My ex has temp custody of our son, our custody hearing is calendared for end of July. Parent evaluator has recommendation that the minor child is not to move more that 20 miles from where he is currently living and this report has been submitted to the court. My ex is planning on sending him to military school in VA this summer. I have only heard about this thru my son and have not been notified by my ex or his atty. Is this legal for my ex to take him out of the state and enroll him in a military school? I thought my ex had to petition the court for approval to move him out-of-state since he only had temp custody. Is it possible to file an exparte to stop this? Any advice is welcomed. Thank you

You may file an ex parte motion to stop your ex from unilaterally deciding to send your son to military school if she is planning to do so prior to the custody trial in July.

What would be the reasons for the exparte? Not proper petitioning of the court and the parent evaluator report. Anything else?

It would be the immediate risk of harm to the child.